bleed screws leak

brokke · 01-26-2003, 10:35 AM

I am having problems with closing the bleed screw of my overhauled alloy S-calipers (2.4 S). All 4 bleed screws of the calipers are renewed, but leak slightly after closing. The bleed screws look exactly the same as the original ones. How much torque may I use to close the bleed screws?

Peter

911 2.4S

Tom F2 · 01-26-2003, 10:45 AM

I have seen this problem on another set of S calipers. I couldn't find a fix. It didn't seem to make the brakes inoperable, i.e., it didn't leak more than a drop here and there. On the other hand, it sounds like a reason why old S calipers might be better as shelf pieces, while nice, fresh cast iron units (such as our sponsor sells) are on your car. Is there really room for compromise on brakes?

HarryD · 01-26-2003, 05:07 PM

You might wnat to get a bit of teflon tape and put one or two wraps around each bleeder screw. Don't use too much and be careful to get it only on the threads and not near the opening.

Quicksilver · 01-26-2003, 07:32 PM

Teflon is a no no. The threads on a bleeder screw don't do any of the sealing. The seal is where the point of the bleeder screw mates against the small hole in the bottom of the hole. Between that mating surface and the threads is a hole that runs from the side of the bleeder screw to the hole running up the middle.

In other words the threads do not provide any sealing. I would simply do a visual check of the hole under the bleeder screw to make sure that it has a nice sharp, undamaged edge. The countersink at the bottom should have a single angle. Also make sure that the bleeders are unworn.

Any chance that you are just seeing a few drops that were left inside the bore of the bleeders?

Wayne

HarryD · 01-26-2003, 07:56 PM

Although most folks tend to disbelieve it, Teflon tape is not a sealant but a thread lubricant that will allow you to tighten the screws a bit easier and therefore get a better seal at the beveled edge.

rfix'n · 01-27-2003, 07:30 AM

I'll probably raise a bit of controversy with the next statement but it worked for me.

I recently put new bleeder valves on all four of my calipers and torqued down to the specified range. They all leaked so I went back and tightened again. A couple, rears, still leaked, I ended up wrenching on them as hard as I could with a 7mm closed end. They quite leaking but it took way more torque then specified.